Aldosterone synthase inhibitor

ABSTRACT

The present invention relates to a compound selected from (R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine and a pharmaceutically acceptable salt thereof, and in particular to the phosphate salt of (R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine, both having preferably an enantiomeric excess of the (R) form higher than or equal to 97%. Furthermore, the present invention relates to pharmaceutical compositions comprising the same, their use as a medicament and in methods of treatment of diseases and disorders in humans including women of child bearing potential and pediatric patients in which aldosterone over-exposure contributes to the deleterious effects of said diseases or disorders, as well as processes for preparing said inventive compounds.

The present invention relates to a compound selected from(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine and apharmaceutically acceptable salt thereof, and in particular to thephosphate salt of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine, bothhaving preferably an enantiomeric excess of the (R) form higher than orequal to 97%. Furthermore, the present invention relates topharmaceutical compositions comprising the same, their use as amedicament and in methods of treatment of diseases and disorders inwhich aldosterone over-exposure contributes to the deleterious effectsof said diseases or disorders including in premenopausal women andpediatric patients, as well as processes for preparing said inventivecompounds.

RELATED ART

Aldosterone synthase (CYP11B2) inhibition has emerged as a new optionfor the treatment of hypertension, heart failure and renal disorders, inaddition to mineralocorticoid receptor (MR) blockade. The aim is todecrease aldosterone concentrations in both plasma and tissues, therebydecreasing MR-dependent and MR-independent effects in the cardiac,vascular and renal target organs. Aldosterone is produced in the zonaglomerulosa of the adrenal gland by the enzymatic action of aldosteronesynthase (CYP11B2) on deoxycorticosterone (M. Azizi et al., Nephrol DialTransplant (2013) 28: 36-43).

Initial attempts to inhibit aldosterone synthesis involved the use ofvarious non-selective inhibitors of steroidogenesis but the same was amajor safety concern. The concept of targeted pharmacological approachto the specific inhibition of aldosterone synthesis was initiated by thediscovery that fadrozole hydrochloride (CGS16949A, INN: Fadrozole; U.S.Pat. Nos. 4,617,307; 4,728,645; 5,098,911), known as a non-steroidalaromatase inhibitor effective for advanced breast cancer treatment,affected aldosterone levels. Subsequent preclinical studies demonstratedthat the R-enantiomer(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinechloride is a potent inhibitor of CYP11B2 while the S-enantiomer isresponsible for the strong and potent aromatase (CYP19) inhibitingactivity of CGS16949A (J. Ménard et al., J Hypertens (2006) 24:993;Fiebeler et al., Circulation (2005) 111:3078-94; Furet et al., J MedChem (1993) 36:1393-1400; U.S. Pat. No. 5,057,521).

On the other hand, and despite its early discovery, clinical developmentof(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinechloride in humans has never been reported and neither a commerciallyviable synthesis nor a satisfying chiral purity has been disclosed (U.S.Pat. No. 4,889,861). In addition,(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinechloride has been found to be highly hygroscopic (Browne L J et al., JMed Chem (1991) 34:725-36; Furet et al., J Med Chem (1993) 36:1393-1400;U.S. Pat. No. 4,889,861).

The chiral purity of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinechloride is in particular of importance in light of the strong andpotent aromatase inhibiting activity of the corresponding (S) enantiomersince extensive evaluation of aromatase inhibitors in clinical trialshas revealed numerous deleterious consequences of aromatase inhibition.Thus, a systematic review and meta-analysis consisting of seven trialsin 30,023 postmenopausal women with breast cancer and treated witharomatase inhibitors revealed significant increases in the occurrence ofbone fractures and cardiovascular disease (Amir et al., J Natl CancerInst (2011) 103:1299-1309). Furthermore, the longer the duration ofaromatase inhibition, the stronger the association with cardiovasculardisease and bone fractures. In addition, in premenopausal women i.e. inwomen of child bearing potential, exposure to aromatase inhibition maylead to reproduction disorders and in lactating women, newborns may beexposed to aromatase-inhibiting compounds via secretion into the breastmilk. Further, in pediatric patients aromatase inhibition may lead todevelopmental disorders. Thus, the need for a very high purity andavoidance of contaminants and impurities of such drugs, which areusually applied for a long period of time or even for lifetime, isevident.

Moreover, and beside the required very high chiral purity and theavoidance of aromatase inhibition as an adverse effect, solubility inwater and stability including enantiomeric stability over an extendedperiod of time in order to exclude any conversion toaromatase-inhibiting moieties, as well as the processability of such adrug, particularly into forms of administration suitable of oraladministration such as tablets, are further combined prerequisites for apharmaceutical preparation of such a drug.

SUMMARY OF THE INVENTION

The inventors have now surprisingly provided(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine offormula (I) with an unprecedented degree of chiral purity i.e.,enantiomeric excess (ee), typically and preferably having an ee of the(R) form higher than or equal to 97%, further preferably even with an eeof the (R) form higher than or equal to 99% or even higher than or equalto 99.5%. Moreover, the inventors have further surprisingly found thatthe phosphate salt of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine, andin particular(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, is non-hygroscopic and stable over an extendedperiod of time, in particular with respect to purity, water content aswell as enantiomeric purity. Furthermore and importantly, the inventorshave surprisingly found that the phosphate salt of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine, andin particular(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate is crystalline in one stable form. In addition, theinventive compounds furthermore possess a decreased and very lowaromatase activity, and consequently an increased and very highaldosterone synthase activity, which makes the inventive compounds verysuitable as candidates for clinical development in humans, in particularfor premenopausal women and pediatric patients. The very low aromataseactivity is believed to be even a prerequisite for clinical developmentand registered use as a medicament to treat diseases and disordersassociated with aldosterone overexposure, in particular forpremenopausal women, and thus women of child bearing potential, andpediatric patients. The latter is in particular true since and althoughthe amount of aromatase and the percentage conversion of androgen toestrogen may be quantitatively small in extra-gonadal tissues, oftenbeing below 1% in any tissue, the effects in terms of hormonal actionstill may be great (Blakemore and Nafiolin, Physiology (2016)31:258-269). Thus, the inventive compounds provide for the possibilityof life-time treatment of disorders negatively affected by aldosteroneproduction due to minimizing the contamination and negative and unwantedeffects caused by the potent aromatase inhibiting (S)-enantiomer.

Accordingly, in a first aspect, the present invention provides for acompound selected from(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine offormula (I) and a pharmaceutically acceptable salt thereof, wherein saidcompound has an ee of the (R) form higher than or equal to 97%,preferably higher than or equal to 98%, more preferably higher than orequal to 99%, and again more preferably higher than or equal to 99.5%,again more preferably higher than or equal to 99.8%, e.g. 99.9%.

In particular, and in a second aspect, the present invention providesfor(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, typically and preferably having an ee of the (R)form higher than or equal to 97%, preferably higher than or equal to98%, more preferably higher than or equal to 99%, and again morepreferably higher than or equal to 99.5%, again more preferably higherthan or equal to 99.8%, e.g. 99.9% and which has been surprisingly foundto be non-hygroscopic and stable over an extended period of time, andhereby in particular with respect to purity, water content and chiralpurity. This in particular important since hygroscopicity typicallyaffects negatively the stability of the active pharmaceuticalingredient. Furthermore and importantly, the phosphate salt of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine, andin particular(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate is crystalline in one stable form. Unstablepolymorphic forms typically affect negatively pharmaceutical efficacyproperties.

Furthermore, the present invention provides in further aspects for(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine aswell as the phosphate salt thereof, preferably the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, typically and preferably having an ee of the (R)form higher than or equal to 97%, preferably higher than or equal to98%, more preferably higher than or equal to 99%, and again morepreferably higher than or equal to 99.5%, again more preferably higherthan or equal to 99.8%, e.g. 99.9%, for use as a medicament and for usein a method of the treatment of a disease or disorder in humansincluding women of child bearing potential and pediatric patients, inwhich aldosterone over-exposure contributes to the deleterious effectsof said disease or disorder, wherein said disease or disorder istypically and preferably selected from primary and secondaryhyperaldosteronism, heart failure, chronic renal failure, hypertension,restenosis, obesity, nephropathy, post-myocardial infarction, renalfibrosis, and coronary heart disease; and wherein further preferablysaid disease or disorder is selected from primary and secondaryhyperaldosteronism. Further preferably, said method is in particularsuited for use in humans including preferably for women of child bearingpotential and pediatric patients.

The achieved inventive chiral resolution and synthesis of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine and(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate in such a high chiral purity allows now thepreparation of pharmaceutical compositions for suppression ofaldosterone, typically and preferably by inhibiting the rate limitingenzyme in aldosterone synthesis, namely aldosterone synthase (CYP11B2),with least possible unwanted contaminating aromatase activity. Thetypical need for life-time treatment of said diseases and disordersreinforces the advantages of the present invention in minimizing thecontamination of the beneficial aldosterone synthase inhibiting(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine or apharmaceutically acceptable salt thereof, and hereby in particular thephosphate salt thereof, and further preferably the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, from the potent aromatase inhibiting(S)-(−)-enantiomer. As presented in Example 8, Tables 10 and 11, theinventive phosphate salt of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine,preferably the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, inhibits aldosterone production (aldosteronesynthase activity) and estradiol production (aromatase activity) byNCI-H295R adrenal cells with IC₅₀'s of 8.1 nM and 5760 nM, respectively;thus demonstrating a more than 700-fold greater inhibition ofaldosterone synthase activity as compared to aromatase activityevidencing a highly beneficial safety profile for the inventivephosphate salt of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine, andfurther the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate. Thus, the present invention is in particularsuited for application in humans, in particular for premenopausal womenand pediatric patients. The very low aromatase activity is believed tobe even a prerequisite for clinical development and use as a medicamentfor aldosterone-associated diseases and disorders, in particular forpremenopausal women, and thus women of child bearing potential, andpediatric patients.

The inventors have found that(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridineprepared by the process of the invention, as well as its phosphate salt,in particular the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, exhibit an unprecedented low inhibitory activityfor aromatase. Accordingly, in a further aspect, the present inventionprovides for(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine or apharmaceutically acceptable salt thereof, in particular the phosphatesalt thereof, more preferably the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, having an IC₅₀ value for aromatase higher than orequal to 700 nM determined by the cell-free human recombinant aromataseenzyme assay described in Example 8, in which the phosphate salt of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine,preferably the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, was found to inhibit aromatase activity with anIC₅₀ of 1640 nM.

Moreover, the inventors have found that(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridineprepared by the process of the invention, as well as its phosphate salt,preferably the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, exhibit an unprecedented high inhibitory activityfor aldosterone synthase. Accordingly, in a further aspect, the presentinvention provides for a compound selected from(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine and apharmaceutically acceptable salt thereof, in particular the phosphatesalt thereof, more preferably the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, wherein said compound inhibits aldosteronesynthase in the NCI-H295R adrenal cell assay described in Example 8 withan IC₅₀ of 100 nM or less.

In a further aspect, the present invention provides for a process forpreparing a compound selected from(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine and apharmaceutically acceptable salt thereof characterized byenantioselective crystallization of the (−)-O,O′-dibenzoyl-L-tartaricacid salt of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine, andwherein very preferably said pharmaceutically acceptable salt is thedihydrogen phosphate thereof.

In a further aspect, the present invention provides for a compoundselected from(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine and apharmaceutically acceptable salt thereof, wherein said compound has aspecific optical rotation [α]_(D) ²⁰ (CH₃CN:H₂O 1:1 (v/v)), [α]_(D) ²⁰(ethanol) or [α]_(D) ²⁵ (ethanol), preferably [α]_(D) ²⁰ (CH₃CN:H₂O1:1(v/v)), of at least +95°, preferably of at least +96°, more preferablyof at least +97°, even more preferably of at least +98°, and whereinpreferably said compound is(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, and wherein further preferably said compoundinhibits aromatase activity in the cell-free human recombinant aromataseenzyme assay described in Example 8 with an IC₅₀ of 700 nM or more,preferably 1000 nM or more, and more preferably 1500 nM or more; andwherein again further preferably said compound inhibits aldosteronesynthase in the NCI-H295R adrenal cell assay described in Example 8 withan IC₅₀ of 100 nM or less, preferably 50 nM or less, and more preferably10 nM or less. In a very preferred embodiment, said compound is(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate and has a specific optical rotation [α]_(D) ²⁰(CH₃CN:H₂O 1:1 (v/v)) of at least +95°, preferably of at least +96°,more preferably of at least +97°, even more preferably of at least +98°,and wherein preferably said compound inhibits aromatase activity in thecell-free human recombinant aromatase enzyme assay described in Example8 with an IC₅₀ of 700 nM or more, preferably 1000 nM or more, and morepreferably 1500 nM or more; and wherein further preferably said compoundinhibits aldosterone synthase in the NCI-H295R adrenal cell assaydescribed in Example 8 with an IC₅₀ of 100 nM or less, preferably 50 nMor less, and more preferably 10 nM or less.

In a further aspect, the present invention provides for a compoundselected from(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine and apharmaceutically acceptable salt thereof, wherein said compound has aspecific optical rotation [α]_(D) ²⁰ (CH₃CN:H₂O 1:1 (v/v)), [α]_(D) ²⁰(ethanol) or [α]_(D) ²⁵ (ethanol), preferably [α]_(D) ²⁰ (CH₃CN:H₂O1:1(v/v)), of at least +95°, preferably of at least +96°, more preferablyof at least +97°, even more preferably of at least +98°, and whereinpreferably said compound is(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, and wherein further preferably said compound has aselectivity for aldosterone synthase over aromatase of 50 or more,preferably 100 or more, most preferably 700 or more; wherein saidselectivity is determined by the ratio of the IC₅₀ values for inhibitionof aromatase and aldosterone synthase; wherein the IC₅₀ values forinhibition of aromatase and aldosterone synthase are both measured,preferably concomitantly, in the NCI-H295R adrenal cell assay describedin Example 8. In a very preferred embodiment, said compound is(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate and has a specific optical rotation [α]_(D) ²⁰(CH₃CN:H₂O 1:1 (v/v)) of at least +95°, preferably of at least +96°,more preferably of at least +97°, even more preferably of at least +98°,and wherein preferably said compound has a selectivity for aldosteronesynthase over aromatase of 50 or more, preferably 100 or more, mostpreferably 700 or more; wherein said selectivity is determined by theratio of the IC₅₀ values for inhibition of aromatase and aldosteronesynthase; wherein the IC₅₀ values for inhibition of aldosterone synthaseand aromatase are both measured, preferably concomitantly, in theNCI-H295R adrenal cell assay described in Example 8.

In a further aspect, the present invention provides for a compoundselected from(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine and apharmaceutically acceptable salt thereof, wherein said compound inhibitsaromatase activity in the cell-free human recombinant aromatase enzymeassay described in Example 8 with an IC₅₀ of 700 nM or more, preferably1000 nM or more, and more preferably 1500 nM or more; and whereinpreferably said compound has an enantiomeric excess of the (R) formhigher than or equal to 97%, and wherein further preferably saidcompound is(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate.

In a further aspect, the present invention provides for a compoundselected from(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine and apharmaceutically acceptable salt thereof, wherein said compound inhibitsaldosterone synthase in the NCI-H295R adrenal cell assay described inExample 8 with an IC₅₀ of 100 nM or less, preferably 50 nM or less, andmore preferably 10 nM or less; and wherein preferably said compound hasan enantiomeric excess of the (R) form higher than or equal to 97%, andwherein further preferably said compound is(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate.

In a further aspect, the present invention provides for a compoundselected from(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine and apharmaceutically acceptable salt thereof, wherein said compound has aselectivity for aldosterone synthase over aromatase of 50 or more,preferably 100 or more, most preferably 700 or more; wherein saidselectivity is determined by the ratio of the IC₅₀ values for inhibitionof aromatase and aldosterone synthase; wherein the IC₅₀ values forinhibition of aldosterone synthase and aromatase are both measured,preferably concomitantly, in the NCI-H295R adrenal cell assay describedin Example 8; and wherein preferably said compound has an enantiomericexcess of the (R) form higher than or equal to 97%, and wherein furtherpreferably said compound is(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate.

DESCRIPTION OF FIGURES

FIG. 1: X-ray powder diffraction (XRPD) diffractogram of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate. The Y-axis of the diffractogram records theintensity in counts per second whereas the X-axis the degrees 2-theta.

FIG. 2: Thermal gravimetric analysis (TGA)/differential scanningcalorimetry (DSC) of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate. The upper panel shows a TGA thermogram of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate. The lower panel shows a DSC thermogram of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate. The thermogram indicates a mass loss of 1.4% up toa temperature of 225° C. (upper panel) which is beyond the melting pointof 189° C. (lower panel). The thermogram indicates a melting point withan onset at 188° C. and peaking at 189° C.

FIG. 3: Chiral purity of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate determined by high pressure liquid chromatography(HPLC). The chromatogram demonstrates an enantiomeric excess of theR-(+) enantiomer (retention time 14.459 min) of higher than 99.9% ee(retention time of the S-(−)-enantiomer: 9.814 min).

FIG. 4: Dynamic vapor sorption (DVS) isotherm plot of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate (overlay of two sorption/desorption cycles).

The dynamic isotherm plot shows a mass increase, respectivelyhygroscopicity of up to 1%.

FIG. 5: Dynamic vapor sorption (DVS) mass plot change of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate (dotted curve: relative change in mass; dashedcurve: target relative humidity (RH)). The mass plot indicates areversible water uptake of up to 1%.

FIG. 6: X-ray powder diffraction (XRPD) diffractograms of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate measured before (upper pattern) and after (lowerpattern) DVS cycles. The overlayed diffractograms indicate that DVStreatment does not affect the reflection patterns respectively thecrystal form.

FIG. 7: Crystal structure and absolute configuration of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate determined by single crystal X-ray analysis. Thesingle X-ray determination confirms the R-(+)-configuration on carbon 5.

DETAILED DESCRIPTION OF THE INVENTION

Unless defined otherwise, all technical and scientific terms used hereinhave the same meanings as commonly understood by one of ordinary skillin the art to which this invention belongs.

The term “about” where used means especially 10%, 5% or 3% (referring tothe given numeric value, respectively), if not indicated otherwise. Ineach of the invention embodiments, “about” can be deleted.

The term “chiral purity” as used herein is defined by the enantiomericexcess (ee) as determined by chiral HPLC (see Examples for details) andcalculated by the equation:

ee=(A _(R) −A _(S))/(A _(R) +A _(S))×100%,

wherein A_(R) is the area of the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine peakin the HPLC chromatogram of the sample solution and A_(S) is the area ofthe (S)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridinepeak in the HPLC chromatogram of the sample solution.

The term “pharmaceutically acceptable salt” as used herein refers to asalt that is pharmaceutically acceptable and that possesses the desiredpharmacological activity of the parent compound. Such salts include acidaddition salts formed with inorganic acids or organic acids known to theskilled person in the art (P. Heinrich Stahl (Editor), Camille G.Wermuth (Editor); Handbook of Pharmaceutical Salts: Properties,Selection, and Use, 2nd Revised Edition, March 2011, Wiley-VCH, ISBN:978-3-90639-051-2). A particularly preferred pharmaceutically acceptablesalt in the present invention is an acid addition salt formed withphosphoric acid, i.e. a dihydrogen phosphate.

The term “phosphate salt” as used in the present application refers tocompounds comprising(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine inits protonated form, i.e. the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinecation and further comprising anions derived from phosphoric acid,wherein said anions are typically and preferably selected fromdihydrogen phosphate [H₂PO₄]⁻ and hydrogen phosphate [HPO₄]²⁻.Preferably, the term “phosphate salt” as used in the present applicationrefers to the compound of formula (I) dihydrogen phosphate, that is,wherein the compound of formula (I) is protonated once and thecounterion is [H₂PO₄]⁻ (see FIG. 7 for single crystal X-ray structure)and, thus, the stoichiometry of mono-protonated(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine todihydrogen phosphate is 1:1. The latter compound is referred herein as(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate.

The term “aromatase” refers to CYP19, a member of the cytochrome P450superfamily, and is also known as estrogen synthase.

The term “aldosterone synthase” refers to the steroid hydroxylasecytochrome P450 enzyme CYP11B2.

The term “amorphous” as used herein, means a supercooled liquid or aviscous liquid which looks like a solid but does not have a regularlyrepeating arrangement of molecules that is maintained over a long rangeand does not have a melting point but rather softens or flows above itsglass transition temperature.

The terms “crystalline” and “crystalline purity” as interchangeably usedherein and related to the inventive compounds, refer to a solid having aregularly repeating arrangement of molecules or external face planes.Preferably, the terms “crystalline” and “crystalline purity” whenreferring to(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate comprising(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate refers to the crystalline form I, wherein saidcrystalline form I is present of at least 60% by total weight,preferably of at least 70% by total weight, further preferably of atleast 80% by total weight, again further preferably of at least 90% bytotal weight, and again further preferably of at least 95% by totalweight. Further components may be, for example, amorphous(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate. Crystalline purity may be determined by means ofXRPD as described herein. Thus, in a preferred embodiment said XRPD canbe determined using the following device, parameters and measuringconditions: Instrument: Bruker AXS D2 PHASER; Irradiation: CuKα (30 kV,10 mA); scan range: 5 to 45° (2 theta value), sample rotation 5 rpm,0.5s/step, 0.010°/step, 3.0 mm detector slit.

The term “crystalline form I” as used herein refers to the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, wherein said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate has an X-ray powder diffraction pattern comprisingthe following 2θ values measured using CuKα radiation: 19.504; 21.919and 24.159, wherein each peak may vary by ±1 or preferably by 0.5, orfurther preferably by ±0.2 degrees. In a preferred embodiment,“crystalline form I” as used herein refers to the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, wherein said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate has an X-ray powder diffraction pattern comprisingthe following 2θ values measured using CuKα radiation, 19.504; 21.919and 24.159, wherein each peak may vary by ±1 or preferably by ±0.5, orfurther preferably by ±0.2 degrees. In a further preferred embodiment,“crystalline form I” as used herein refers to the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, wherein said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate has an X-ray powder diffraction pattern comprisingthe following 2θ values measured using CuKα radiation, 19.504; 21.919and 24.159, wherein each peak may vary by ±0.5, or preferably by ±0.2degrees. In again a further preferred embodiment, the term “crystallineform I” as used herein refers to the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, wherein said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate has an X-ray powder diffraction pattern comprisingthe following 2θ values measured using CuKα radiation, 19.504; 21.919and 24.159, wherein each peak may vary by ±0.2 degrees. In anotherpreferred embodiment, “crystalline form I” as used herein refers to the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, wherein said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate has an X-ray powder diffraction pattern comprisingthe following 2θ values measured using CuKα radiation: 19.504; 21.919;24.159; 16.003; 26.101; 27.168; 27.542 and 29.029, wherein each peak mayvary by ±1 or preferably by ±0.5, or further preferably by ±0.2 degrees.In another preferred embodiment, “crystalline form I” as used hereinrefers to the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, wherein said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate has an X-ray powder diffraction pattern comprisingthe following 2θ values measured using CuKα radiation: 19.504; 21.919;24.159; 16.003; 26.101; 27.168; 27.542 and 29.029, wherein each peak mayvary by ±0.5, or preferably by ±0.2 degrees.

The term “anhydrous” as used herein refers to a crystalline form whichcontains less than 3%, preferably less than 2.5%, more preferably lessthan 2%, more preferably less than 1.5%, most preferably less than 1%water of hydration.

The term “non-hygroscopic” means the ability by the inventivepharmaceutically acceptable salts of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine, andin particular of the phosphate salt of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine, morepreferably the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, when they occur as powders or granules, towithstand exposure to the water vapor of an ambient atmosphere for 24hours, weeks, months or years as a premise for commercial use withoutgiving rise to adverse phenomena of aggregating, agglomerating,absorbing water, or deliquescing. Typically and preferably, the term“non-hygroscopic” as used herein and referring to the phosphate salt of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine, andpreferably when referring to the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, means that on storage in the open under normalambient conditions, typically and preferably at 20-25° C. and a relativehumidity of between 20% and 80%, preferably between 30% and 60%, itpreserves its consistency as (preferably free-flowing) powder orgranules over a period of at least one day, preferably one week, furtherpreferably one month, again further preferably over a period of at least3 months, and again further preferably for at least 6 months, and againfurther preferably or at least 1 year or more, in particular, to meetregulatory ICH standards. Further preferably, the term “non-hygroscopic”as used herein and referring to the phosphate salt of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine, andpreferably when referring to the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, means that on storage in the open under normalambient conditions, typically and preferably at 20-25° C. and a relativehumidity of between 20% and 80%, preferably between 30% and 60%, for aperiod of 24 hours, typically and preferably as determined in Example 5,it shows a weight increase of less than 5%, preferably of less than 3%,further preferably of less than 2%, again further preferably of lessthan 1%. Again further preferably, the term “non-hygroscopic” as usedherein and referring to the phosphate salt of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine, andpreferably when referring to the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, means that on storage in the open under normalambient conditions, typically and preferably at room temperature, mostpreferably at 20-25° C. and at a relative humidity of between 20% and80%, preferably between 30% and 60%, for a period of 24 hours, typicallyand preferably as determined in Example 5, said phosphate salt,preferably said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate shows a water uptake of less than 5% (wt/wt),preferably of less than 3% (wt/wt), further preferably of less than 2%(wt/wt), again further preferably of less than 1% (wt/wt). Alternativelypreferred, the term “non-hygroscopic” as used herein and referring tothe phosphate salt of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine, andpreferably when referring to the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, means that on storage in the open under normalambient conditions, typically and preferably at 25° C. and a relativehumidity of between of about 60%, for a period of 24 hours, preferablyfor a period of one month, further preferably for a period of at least 3months, and again further preferably for at least 6 months, and againfurther preferably or at least 1 year, typically and preferably asdetermined in Example 9, the water content is less than 0.5 w/w %,preferably less than 0.4 w/w %, and further preferably equal or lessthan 0.3 w/w %.

The term “pharmaceutically acceptable excipient” as used herein includesany physiologically inert additive that is routinely used inpharmaceutical dosage forms. Pharmaceutically acceptable excipients areselected from the group comprising binders, diluents, carriers,lubricants, glidants, coating additives or combinations thereof.

The term “solubility” as used herein refers to simplified descriptivesolubilities (e.g. in water) in accordance with the U.S. Pharmacopoeia,Chapter “General Notices”, § 5.30 “Description and Solubility” (and asdefined below):

Parts of Solvent Required Descriptive Term for 1 Part of Solute Verysoluble Less than 1 Freely soluble From 1 to 10 Soluble From 10 to 30Sparingly soluble From 30 to 100 Slightly soluble From 100 to 1,000 Veryslightly soluble From 1,000 to 10,000 Practically insoluble, or Greaterthan or equal to Insoluble 10,000

The term “woman of childbearing potential” as used herein refers to apremenopausal female capable of becoming pregnant.

The term “pediatric patient” as used herein refers to patient in the agecategory 0-18, preferably 0-16 years and include preterm and termnewborn infants (0-27 days), infants and toddlers (28 days to 23months), children (2-11 years) and adolescents (2 to 16/18 years).

Accordingly, in one embodiment, there is provided a compound selectedfrom (R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridineof formula (I) and a pharmaceutically acceptable salt thereof, inparticular(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, having a solubility in water of more than 50%vol/vol.

The expression “IC₅₀” refers to the half maximal inhibitoryconcentration as commonly known in the art. The IC₅₀ for aromatase isdetermined by the cell-free human recombinant aromatase assay describedin Example 8. The IC₅₀ for aldosterone synthase is determined by thehuman NCI-H295R cell assay described in Example 8. When referring to“selectivity for aldosterone synthase over aromatase”, the followingratio is meant:

${selectivity} = \frac{{IC}\; 50\mspace{14mu} {for}\mspace{14mu} {aromatase}}{{IC}\; 50\mspace{14mu} {for}\mspace{14mu} {aldosterone}\mspace{14mu} {synthase}}$

wherein both the IC₅₀ for aldosterone synthase and the IC₅₀ foraromatase are determined, preferably concomitantly, by the humanNCI-H295R cell assay described in Example 8.

As outlined above, the phosphate salt of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine,preferably the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, inhibits aldosterone production (aldosteronesynthase activity) and estradiol production (aromatase activity) byNCI-H295R adrenal cells with IC₅₀'s of 8.1 nM and 5760 nM, respectively(Example 8, Tables 10 and 11); thus demonstrating a selectivity of about700 for aldosterone synthase over aromatase.

As used herein, the term “a disorder” or “a disease” refers to anyderangement or abnormality of function; a morbid physical or mentalstate. See Dorland's Illustrated Medical Dictionary (VSIB. Saunders Co.27th ed. 1988).

As used herein, the expression “disease or disorder in which aldosteroneover-exposure contributes to the deleterious effects of said disease ordisorder” preferably refers to a disease and disorder which is due tothe abnormal or inappropriate activity/expression of aldosteronesynthase and the biological activity or process which is associated withthe abnormal or inappropriate expression of aldosterone synthase.Typical examples of diseases or disorders that are due to abnormal orinappropriate activity/expression of aldosterone synthase are primaryand secondary hyperaldosteronism, heart failure, chronic renal failure,hypertension, restenosis, obesity, nephropathy, post-myocardialinfarction, renal fibrosis, and coronary heart disease.

As used herein, the term “abnormal activity of aldosterone synthase”refers to an activity of aldosterone synthase which differs from theactivity of the wild-type or native gene or protein, or which differsfrom the activity of the gene or protein in a healthy subject. Theabnormal activity can be stronger or weaker than the normal activity.

As used herein, the term “inappropriate activity of aldosteronesynthase” refers to the activity of aldosterone synthase of thewild-type or native gene or protein or to the activity of the gene orprotein in a healthy subject, which is considered as appropriate in ahealthy subject, but the same said activity is considered inappropriatefor a diseased subject, i.e. said activity is too strong or too weak fora diseased subject.

As used herein, the term “treating” or “treatment” of any disease ordisorder refers to ameliorating the disease or disorder (i.e., arrestingor reducing the development of the disease or at least one of theclinical symptoms thereof).

As used herein, the term “specific optical rotation” refers to thespecific optical rotation of a solution of the respective compound in asolvent, wherein said solvent is typically and preferably ethanol orCH₃CN:H₂O 1:1 (v/v), further preferably CH₃CN:H₂O 1:1 (v/v), and whereinsaid specific optical rotation is calculated by the formula:100×α/(1×c), wherein α=observed rotation in degrees; 1=cell path lengthin decimeters; c=concentration in grams per 100 ml, and wherein themeasurement is performed at the sodium D line (i.e. 589.3 nm) at roomtemperature, typically and preferably at either 20° C. or 25° C. Theterm “specific optical rotation” is abbreviated as [α]_(D) ²⁰ or [α]_(D)²⁵. Typically, for [α]D²⁰ or [α]D²⁵, either the sign of the rotation (+or −) and its actual value is indicated herein or [α]_(D) ²⁰ or [α]_(D)²⁵ is provided by way of its sign of the rotation (+ or −) and itsactual value indicated in degrees (°). The complete unit as determinedabove (deg dm⁻¹ cm³ g⁻¹) is typically omitted for the sake of clarity.

In a first aspect, the present invention provides for a compoundselected from(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine offormula (I) and a pharmaceutically acceptable salt thereof having anenantiomeric excess (ee) of the (R) form higher than or equal to 97%,preferably higher than or equal to 98%, more preferably higher than orequal to 99%, and again more preferably higher than or equal to 99.5%,again more preferably higher than or equal to 99.8%, e.g. 99.9%.

In particular, and in a second aspect, the present invention providesfor(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, typically and preferably having an ee of the (R)form higher than or equal to 97%, preferably higher than or equal to98%, more preferably higher than or equal to 99%, and again morepreferably higher than or equal to 99.5%, again more preferably higherthan or equal to 99.8%, e.g. 99.9% and which has been surprisingly foundto be non-hygroscopic and stable over an extended period of time, inparticular with respect to purity, water content and chiral purity.Furthermore and importantly, the phosphate salt of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine, andin particular(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate is crystalline in one stable form, typically andpreferably in said crystalline form I.

The water uptake of the inventive(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate as measured by Dynamic Vapour Sorption studies isless than 1% at greater than 90% humidity (FIG. 4) and in addition thewater uptake is reversible (FIG. 5). Furthermore, the mass loss uponheating up to a temperature of 225° C. was only 1.4% (FIG. 2). Inconclusion, the inventive phosphate salt, preferably the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, is not hygroscopic. As a consequence, theinventive(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate can be stored in bulk in customary pharmaceuticalcontainment vessels at ambient conditions. Moreover, the inventive(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate has been found to be highly crystalline and havinga high level of crystalline purity. Furthermore, and surprisingly theinventive(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate with the described exceptional chiral purity ispresent in one single crystalline form with a defined x-ray structureand R-(+)-absolute configuration on carbon 5, its chiral center (FIG. 1and Table 1; FIG. 7).

Multiple crystalline forms—so called polymorphs—complicate themanufacturing of pharmaceutical preparations because such forms caninterconvert requiring additional provisions to prevent suchinterconversion. Different polymorphs behave differently in theformulation of pharmaceutical products; they can affect micronization,tablet formation, solubility and also bioavailability. Since even thesmallest compound may have hundreds of thousands of possiblearrangements of its molecules in a solid crystal, predicting crystalstructures and their properties are a great scientific challenge and itis not possible to know a priori whether polymorphism will actuallyoccur for a given molecule. Polymorphism is thus a serious concern whenseeking to provide safe and efficacious forms of a drug. Despite this,the inventors have discovered that the crystalline form I of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate is physically stable, i.e. polymorphism was notobserved (Example 6, Table 8; Example 7, Table 9 and FIG. 6, Example 9)and can be obtained predictably and reliably (Example 3, step 4).Furthermore, XRPD analysis of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate (FIG. 1 and Table 1) showed that the substance wasessentially free of amorphous material (i.e. amorphous material was notdetectable). XRPD was performed, if not described otherwise, asdescribed in the Examples section.

Thus, in one embodiment, the present invention provides crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, preferably anhydrous crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, more preferably anhydrous crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate having an ee of the (R) form higher than or equalto 97%, preferably higher than or equal to 98%, more preferably higherthan or equal to 99%, and again more preferably higher than or equal to99.5%, again more preferably higher than or equal to 99.8%, e.g. 99.9%.

The crystals of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate (crystalline form I) are characterized by XRPD(FIG. 1) with the following angles, lattice spacings (d values) andrelative line intensities (intensity) of their X-ray powder pattern(Table 1).

TABLE 1 XRPD Peak list of (R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridine dihydrogen phosphatecrystalline form I Index 2θ Angle d Value Relative Intensity 1 6.02312914.6619 0.1166064 2 9.969034 8.865584 0.04637039 3 11.26224 7.8503130.01466121 4 11.22848 7.873846 0.01766241 5 11.96566 7.390353 0.079380316 12.77761 6.922504 0.07618304 7 13.79347 6.414874 0.06721209 8 14.393146.148929 0.08399912 9 15.3394 5.771677 0.09292314 10 16.00317 5.5337460.2509092 11 16.27337 5.442465 0.1271836 12 17.07502 5.188714 0.0181443813 17.27593 5.128821 0.06430446 14 17.9904 4.926713 0.09392752 1518.38238 4.822532 0.07743008 16 18.65471 4.752738 0.07315308 17 18.960964.676658 0.07685736 18 19.14281 4.632641 0.1232251 19 19.504 4.5476570.9732185 20 20.01265 4.433205 0.1459729 21 20.58808 4.310579 0.0642726822 20.43302 4.34294 0.03934043 23 20.72112 4.283203 0.1308791 2421.12683 4.201858 0.09223638 25 21.91906 4.051746 1.00000000 26 22.592023.932552 0.0988786 27 24.44788 3.63807 0.1554819 28 24.15917 3.6808870.6751482 29 24.48119 3.633195 0.1650803 30 25.70071 3.463495 0.0563096631 26.10094 3.411286 0.1425888 32 26.58127 3.350723 0.02198978 3327.16767 3.279716 0.1315578 34 27.54165 3.236025 0.09750613 35 27.714083.216282 0.01282637 36 28.27603 3.153627 0.01739924 37 28.09725 3.1732850.004438166 38 28.54909 3.124082 0.02253263 39 29.02939 3.0734750.2474836 40 29.71314 3.004288 0.01214569 41 30.07578 2.9688840.04296284 42 30.68808 2.911028 0.01120924 43 30.92867 2.888930.02964231 44 31.6379 2.825768 0.0454447 45 32.27005 2.771842 0.0127368146 32.79806 2.728414 0.01504905 47 33.20638 2.695791 0.04151051 4833.23304 2.693689 0.04147112 49 33.65808 2.660638 0.009918388 5034.41793 2.603618 0.02669827 51 34.35512 2.608234 0.03452484 52 35.021422.560122 0.01117852 53 35.06671 2.556919 0.01513675 54 35.68978 2.5136960.03497554 55 35.93622 2.497021 0.01164656 56 36.50305 2.4595370.004599076 57 36.56591 2.455453 0.004500904 58 36.92023 2.4326970.01221618 59 37.14021 2.418792 0.01601023 60 37.89624 2.3722570.03661312 61 39.60815 2.27358 0.01607032 62 40.22464 2.2401450.004137916

In one embodiment there is provided a crystalline form I of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, characterized by an X-ray powder diffractionpattern comprising the following 2θ values measured as described in theExamples section: 19.504; 21.919 and 24.159. In one embodiment there isprovided a crystalline form I of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, characterized by an X-ray powder diffractionpattern comprising the following 2θ values measured as described in theExamples section: 19.504; 21.919 and 24.159, wherein each peak may varyby ±1 or preferably by ±0.5, or further preferably by ±0.2 degrees. In apreferred embodiment, said X-ray powder diffraction pattern furthercomprises the following 2θ values: 16.003; 26.101; 27.168; 27.542 and29.029. In a preferred embodiment, said X-ray powder diffraction patternfurther comprises the following 2θ values: 16.003; 26.101; 27.168;27.542 and 29.029, wherein each peak may vary by ±1 or preferably by±0.5, or further preferably by ±0.2 degrees. In a particularly preferredembodiment, there is provided a crystalline form I of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, characterized by an X-ray powder diffractionpattern comprising at least one, more preferably 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16 or all of the following 2θ values: 6.023129;9.969034; 11.26224; 11.22848; 11.96566; 12.77761; 13.79347; 14.39314;15.3394; 16.00317; 16.27337; 17.07502; 17.27593; 17.9904; 18.38238;18.65471; 18.96096; 19.14281; 19.504; 20.01265; 20.58808; 20.43302;20.72112; 21.12683; 21.91906; 22.59202; 24.44788; 24.15917; 24.48119;25.70071; 26.10094; 26.58127; 27.16767; 27.54165; 27.71408; 28.27603;28.09725; 28.54909; 29.02939; 29.71314; 30.07578; 30.68808; 30.92867;31.6379; 32.27005; 32.79806; 33.20638; 33.23304; 33.65808; 34.41793;34.35512; 35.02142; 35.06671; 35.68978; 35.93622; 36.50305; 36.56591;36.92023; 37.14021; 39.60815; 37.89624 and 40.22464. In anotherparticularly preferred embodiment, there is provided a crystalline formI of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, characterized by an X-ray powder diffractionpattern comprising at least one, more preferably 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16 or all of the following 2θ values: 6.023129;9.969034; 11.26224; 11.22848; 11.96566; 12.77761; 13.79347; 14.39314;15.3394; 16.00317; 16.27337; 17.07502; 17.27593; 17.9904; 18.38238;18.65471; 18.96096; 19.14281; 19.504; 20.01265; 20.58808; 20.43302;20.72112; 21.12683; 21.91906; 22.59202; 24.44788; 24.15917; 24.48119;25.70071; 26.10094; 26.58127; 27.16767; 27.54165; 27.71408; 28.27603;28.09725; 28.54909; 29.02939; 29.71314; 30.07578; 30.68808; 30.92867;31.6379; 32.27005; 32.79806; 33.20638; 33.23304; 33.65808; 34.41793;34.35512; 35.02142; 35.06671; 35.68978; 35.93622; 36.50305; 36.56591;36.92023; 37.14021; 39.60815; 37.89624 and 40.22464, wherein each peakmay vary by ±1 or preferably by ±0.5, or further preferably by ±0.2degrees. In another particularly preferred embodiment, there is provideda crystalline form I of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, characterized by an X-ray powder diffractionpattern comprising at least one, more preferably 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16 or all of the following 2θ values: 6.023129;9.969034; 11.26224; 11.22848; 11.96566; 12.77761; 13.79347; 14.39314;15.3394; 16.00317; 16.27337; 17.07502; 17.27593; 17.9904; 18.38238;18.65471; 18.96096; 19.14281; 19.504; 20.01265; 20.58808; 20.43302;20.72112; 21.12683; 21.91906; 22.59202; 24.44788; 24.15917; 24.48119;25.70071; 26.10094; 26.58127; 27.16767; 27.54165; 27.71408; 28.27603;28.09725; 28.54909; 29.02939; 29.71314; 30.07578; 30.68808; 30.92867;31.6379; 32.27005; 32.79806; 33.20638; 33.23304; 33.65808; 34.41793;34.35512; 35.02142; 35.06671; 35.68978; 35.93622; 36.50305; 36.56591;36.92023; 37.14021; 39.60815; 37.89624 and 40.22464, wherein each peakmay vary by ±0.5, or preferably by ±0.2 degrees. In one embodiment, thethree largest peaks of crystalline form I in the XRPD diffractogram havea relative intensity of 1 to 0.85 to 0.55, especially of 1 to 0.9 to0.6, more especially of 1 to 0.95 to 0.65, e.g. of 1 to 0.97 to 0.68(obtainable by integration of each of the peaks in the XRPD diagrams).In a particular embodiment the largest peak is at a 2-theta (θ) value ofabout 21.919 and the second-largest peak is at a 2-theta (θ) value ofabout 19.504 and the third-largest peak is at a 2-theta (θ) value ofabout 24.159, respectively. In a further particular embodiment thelargest peak is at a 2-theta (θ) value of about 21.919±0.5, orpreferably by ±0.2 degrees, and the second-largest peak is at a 2-theta(θ) value of about 19.504±0.5, or preferably by ±0.2 degrees and thethird-largest peak is at a 2-theta (θ) value of about 24.159±0.5, orpreferably by ±0.2 degrees, respectively. Preferred is the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate showing an XRPD diffractogram as shown in FIG. 1.

It was further surprisingly found that(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate (crystalline form I) has a single sharp and highmelting point of 189° C. as measured by DSC (FIG. 2), again indicatinghigh physical stability and which is further very beneficial withregards to drug manufacture, storage and processing to pharmaceuticalformulations. Accordingly, in one embodiment, there is provided(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate having a melting point of equal or between 184° C.to 193° C., and wherein preferably said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate has a melting point of equal or between 188° C. to190° C., typically and preferably using thermogravimetryanalysis/differential scanning calorimetry (TGA/DSC). In a furtherembodiment, there is provided(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate having a melting point of 184° C., 185° C., 186°C., 187° C., 188° C., 189° C., 190° C., 191° C., 192° C., 193° C. or194° C., most preferably 189° C. In a further embodiment, there isprovided(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate having a melting point of 189±5° C., 189±2° C.,189±1° C. or 189±0.5° C. The melting temperatures herein, if notdescribed otherwise, are obtained by TGA/DSC as described in theExamples section.

In addition, the inventors have found that the solubility of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate (crystalline form I) is low in a number ofnon-aqueous solvents (Example 6, Table 7) which are thus anti-solventsfor the salt, thus making it possible to achieve good precipitation andthus good yields and good purity. On the other hand, crystalline form Iis very soluble in water (Example 6, Table 8), which is advantageous forproviding oral or parenteral formulations.

The(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate prepared from the enantiomerically pure(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine freebase described herein and thus having an ee of >99.9%, was found to havea specific optical rotation ([α]_(D) ²⁰) of +98.1° (CH₃CN:H₂O 1:1 (v/v);Example 3).

Accordingly, in one very preferred embodiment and aspect of the presentinvention, there is provided(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate having a specific optical rotation ([α]_(D) ²⁰)(CH₃CN:H₂O 1:1 (v/v)) of at least +94°, preferably of at least +95°,further preferably of at least +96°, more preferably of at least +97°,even more preferably of at least +98°.

In a further embodiment, the present invention provides for(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridinehaving a specific optical rotation [α]_(D) ² (ethanol) of at least+120°, preferably of at least +121°, further preferably of at least+122°, again further preferably of at least +123°, again furtherpreferably of at least +124°, again further preferably of at least+125°, again further preferably of at least +126°, and again furtherpreferably of at least +127°. In another embodiment, the presentinvention provides for(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinechloride having a specific optical rotation [α]_(D) ²⁰ (ethanol) of atleast +95°, preferably of at least +96°, further preferably of at least+97°, more preferably of at least +98°, even more preferably of at least+99°, further preferably of at least +100°, more preferably of at least+101, even more preferably of at least +102°, and again more preferablyof at least +103°, even more preferably of at least +104°.

In a very preferred aspect, the present invention provides(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, preferably crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, more preferably anhydrous crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate.

In again a very preferred embodiment and aspect, the present inventionprovides(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, preferably crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, more preferably anhydrous crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, having an ee of the (R) form higher than or equalto 97%, preferably higher than or equal to 98%, more preferably higherthan or equal to 99%, and again more preferably higher than or equal to99.5%, again more preferably higher than or equal to 99.8%, e.g. 99.9%.

In again a very preferred embodiment and aspect, the present inventionprovides crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, preferably anhydrous crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, having an ee of the (R) form higher than or equalto 97%, preferably higher than or equal to 98%, more preferably higherthan or equal to 99%, and again more preferably higher than or equal to99.5%, again more preferably higher than or equal to 99.8%, e.g. 99.9%,and wherein preferably said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate is a crystalline form I of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, wherein said crystalline form I has an X-raypowder diffraction pattern comprising the following 2θ values measuredusing CuKα radiation: 19.504; 21.919 and 24.159, wherein each peak mayvary by ±0.5, or preferably by ±0.2 degrees.

In again a very preferred embodiment and aspect, the present inventionprovides crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, preferably anhydrous crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, having an ee of the (R) form higher than or equalto 97%, preferably higher than or equal to 98%, more preferably higherthan or equal to 99%, and again more preferably higher than or equal to99.5%, again more preferably higher than or equal to 99.8%, e.g. 99.9%,and wherein said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate is a crystalline form I of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, wherein said crystalline form I has an X-raypowder diffraction (XRPD) pattern comprising the following 2θ valuesmeasured using CuKα radiation: 19.504; 21.919 and 24.159, wherein eachpeak may vary by ±0.5, or preferably by ±0.2 degrees, wherein preferablysaid XRPD can be determined using the following device, parameters andmeasuring conditions: Instrument: Bruker AXS D2 PHASER; Irradiation:CuKα (30 kV, 10 mA); scan range: 5 to 45° (2 theta value), samplerotation 5 rpm, 0.5s/step, 0.010°/step, 3.0 mm detector slit.

In again a very preferred embodiment and aspect, the present inventionprovides crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, preferably anhydrous crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, having an ee of the (R) form higher than or equalto 97%, preferably higher than or equal to 98%, more preferably higherthan or equal to 99%, and again more preferably higher than or equal to99.5%, again more preferably higher than or equal to 99.8%, e.g. 99.9%,and wherein said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate is a crystalline form I of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, wherein said crystalline form I has an X-raypowder diffraction pattern comprising the following 2θ values measuredusing CuKα radiation: 19.504; 21.919 and 24.159, wherein each peak mayvary by ±0.5, or preferably by ±0.2 degrees, said XRPD can be determinedusing the following device, parameters and measuring conditions:Instrument: Bruker AXS D2 PHASER; Irradiation: CuKα (30 kV, 10 mA); scanrange: 5 to 45° (2 theta value), sample rotation 5 rpm, 0.5s/step,0.010°/step, 3.0 mm detector slit.

(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate has further been found to be anhydrous (Example 3and 5). Thus, in one embodiment, the present invention provides foranhydrous(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate. In a particularly preferred embodiment, thepresent invention provides for anhydrous(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate having an ee of the (R) form higher than or equalto 97%, preferably higher than or equal to 98%, more preferably higherthan or equal to 99%, and again more preferably higher than or equal to99.5%, again more preferably higher than or equal to 99.8%, e.g. 99.9%.

In a further particularly preferred embodiment, the present inventionprovides for anhydrous(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate crystalline form I.

In yet a further particularly preferred embodiment, the presentinvention provides for anhydrous(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate crystalline form I as defined herein, having an eeof the (R) form higher than or equal to 97%, preferably higher than orequal to 98%, more preferably higher than or equal to 99%, and againmore preferably higher than or equal to 99.5%, again more preferablyhigher than or equal to 99.8%, e.g. 99.9%.

As outlined above, the inventors have surprisingly found that(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridineprepared by the process of the invention (Example 3), as well as itsphosphate salt, preferably the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, exhibit an unprecedented low inhibitory activityfor aromatase (Example 8), which is crucial to avoid side effectsrelated to inhibition of aromatase when using the compounds of theinvention in methods of treating diseases or disorders related toenhanced aldosterone synthase activity and/or enhanced levels ofaldosterone, in particular when used for women of child bearingpotential and pediatric patients. Accordingly, in a further aspect, thepresent invention provides for a compound selected from(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine and apharmaceutically acceptable salt thereof, in particular the phosphatesalt thereof, further preferably the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, wherein said compound inhibits aromatase activityin the cell-free human recombinant aromatase enzyme assay described inExample 8 with an IC₅₀ of 700 nM or more, preferably 750 nM or more,more preferably 800 nM or more, more preferably 850 nM or more, morepreferably 900 nM or more, more preferably 950 nM or more, morepreferably 1000 nM or more, more preferably 1050 nM or more, morepreferably 1100 nM or more, more preferably 1150 nM or more, morepreferably 1200 nM or more, more preferably 1250 nM or more, morepreferably 1300 nM or more, more preferably 1350 nM or more, morepreferably 1400 nM or more, more preferably 1450 nM or more, morepreferably 1500 nM or more, more preferably 1550 nM or more, mostpreferably at least 1600 nM, e.g. 1610 nM or 1620 nM or 1630 nM or 1640nM or at least 1650 nM.

In yet a further aspect, the present invention provides for a compoundselected from(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine and apharmaceutically acceptable salt thereof, in particular the phosphatesalt thereof, further preferably the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, wherein said compound inhibits aldosteronesynthase in the NCI-H295R adrenal cell assay described in Example 8 withan IC₅₀ of 100 nM or less. In one embodiment, the compounds of theinvention inhibit aldosterone synthase in the NCI-H295R adrenal cellassay described in Example 8 with an IC₅₀ of 90 nM or less, 80 nM orless, 70 nM or less, 60 nM or less, 50 nM or less, 40 nM or less, 35 nMor less, 30 nM or less, 25 nM or less, or 20 nM or less; in particular15 nM or less, e.g., 15 nM, 14 nM, 13 nM, 12 nM, 11 nM, 10 nM, 9 nM, 8nM, 7 nM, 6 nM, 5 nM, 4 nM, 3 nM, 2 nM or 1 nM or less. In a preferredembodiment, the compounds of the invention inhibit aldosterone synthasein the NCI-H295R adrenal cell assay described in Example 8 with an IC₅₀of 10 nM or less.

In yet a further aspect, the present invention provides for a compoundselected from(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine and apharmaceutically acceptable salt thereof, wherein said compound has aselectivity for aldosterone synthase over aromatase of 30 or more,preferably 50 or more, more preferably 100 or more, more preferably 150or more, more preferably 200 or more, more preferably 250 or more, morepreferably 300 or more, more preferably 350 or more, more preferably 400or more, more preferably 450 or more, more preferably 500 or more, morepreferably 550 or more, more preferably 600 or more, more preferably 650or more, most preferably 700 or more, wherein said selectivity isdetermined by the ratio of the IC₅₀ values for inhibition of aromataseand aldosterone synthase; and wherein the IC₅₀ values for inhibition ofaldosterone synthase and aromatase are both measured, preferablyconcomitantly, in the NCI-H295R adrenal cell assay described in Example8.

Thus, in again a very preferred embodiment and aspect, the presentinvention provides crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, preferably anhydrous crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, having an ee of the (R) form higher than or equalto 97%, preferably higher than or equal to 98%, more preferably higherthan or equal to 99%, and again more preferably higher than or equal to99.5%, again more preferably higher than or equal to 99.8%, e.g. 99.9%,wherein said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate is a crystalline form I of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, wherein said crystalline form I has an X-raypowder diffraction pattern comprising the following 2θ values measuredusing CuKα radiation: 19.504; 21.919 and 24.159, wherein each peak mayvary by ±0.5, or preferably by ±0.2 degrees, said XRPD can typically andpreferably be determined using the following device, parameters andmeasuring conditions: Instrument: Bruker AXS D2 PHASER; Irradiation:CuKα (30 kV, 10 mA); scan range: 5 to 45° (2 theta value), samplerotation 5 rpm, 0.5s/step, 0.010°/step, 3.0 mm detector slit, andwherein said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate inhibits aromatase activity in the cell-free humanrecombinant aromatase enzyme assay described in Example 8 with an IC₅₀of 700 nM or more, preferably 750 nM or more, more preferably 800 nM ormore, more preferably 850 nM or more, more preferably 900 nM or more,more preferably 950 nM or more, more preferably 1000 nM or more, morepreferably 1050 nM or more, more preferably 1100 nM or more, morepreferably 1150 nM or more, more preferably 1200 nM or more, morepreferably 1250 nM or more, more preferably 1300 nM or more, morepreferably 1350 nM or more, more preferably 1400 nM or more, morepreferably 1450 nM or more, more preferably 1500 nM or more, morepreferably 1550 nM or more, most preferably at least 1600 nM, e.g. 1610nM or 1620 nM or 1630 nM or 1640 nM or at least 1650 nM.

In again a very preferred embodiment and aspect, the present inventionprovides crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, preferably anhydrous crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, having an ee of the (R) form higher than or equalto 97%, preferably higher than or equal to 98%, more preferably higherthan or equal to 99%, and again more preferably higher than or equal to99.5%, again more preferably higher than or equal to 99.8%, e.g. 99.9%,wherein said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate is a crystalline form I of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, wherein said crystalline form I has an X-raypowder diffraction pattern comprising the following 2θ values measuredusing CuKα radiation: 19.504; 21.919 and 24.159, wherein each peak mayvary by ±0.5, or preferably by ±0.2 degrees, said XRPD can typically andpreferably be determined using the following device, parameters andmeasuring conditions: Instrument: Bruker AXS D2 PHASER; Irradiation:CuKα (30 kV, 10 mA); scan range: 5 to 45° (2 theta value), samplerotation 5 rpm, 0.5s/step, 0.010°/step, 3.0 mm detector slit, andwherein said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate inhibits aldosterone synthase in the NCI-H295Radrenal cell assay described in Example 8 with an IC₅₀ of 90 nM or less,80 nM or less, 70 nM or less, 60 nM or less, 50 nM or less, 40 nM orless, 35 nM or less, 30 nM or less, 25 nM or less, or 20 nM or less; inparticular 15 nM or less, e.g., 15 nM, 14 nM, 13 nM, 12 nM, 11 nM, 10nM, 9 nM, 8 nM, 7 nM, 6 nM, 5 nM, 4 nM, 3 nM, 2 nM or 1 nM or less. In apreferred embodiment, the compounds of the invention inhibit aldosteronesynthase in the NCI-H295R adrenal cell assay described in Example 8 withan IC₅₀ of 10 nM or less.

In again a very preferred embodiment and aspect, the present inventionprovides crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, preferably anhydrous crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, having an ee of the (R) form higher than or equalto 97%, preferably higher than or equal to 98%, more preferably higherthan or equal to 99%, and again more preferably higher than or equal to99.5%, again more preferably higher than or equal to 99.8%, e.g. 99.9%,wherein said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate is a crystalline form I of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, wherein said crystalline form I has an X-raypowder diffraction pattern comprising the following 2θ values measuredusing CuKα radiation: 19.504; 21.919 and 24.159, wherein each peak mayvary by ±0.5, or preferably by ±0.2 degrees, said XRPD can typically andpreferably be determined using the following device, parameters andmeasuring conditions: Instrument: Bruker AXS D2 PHASER; Irradiation:CuKα (30 kV, 10 mA); scan range: 5 to 45° (2 theta value), samplerotation 5 rpm, 0.5s/step, 0.010/step, 3.0 mm detector slit, and whereinsaid(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate has a selectivity for aldosterone synthase overaromatase of 30 or more, preferably 50 or more, more preferably 100 ormore, more preferably 150 or more, more preferably 200 or more, morepreferably 250 or more, more preferably 300 or more, more preferably 350or more, more preferably 400 or more, more preferably 450 or more, morepreferably 500 or more, more preferably 550 or more, more preferably 600or more, more preferably 650 or more, most preferably 700 or more,wherein said selectivity is determined by the ratio of the IC₅₀ valuesfor inhibition of aromatase and aldosterone synthase; and wherein theIC₅₀ values for inhibition of aldosterone synthase and aromatase areboth measured, preferably concomitantly, in the NCI-H295R adrenal cellassay described in Example 8.

In one aspect, the present invention provides for(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridinehaving an ee of the (R) form higher than or equal to 97%, preferablyhigher than or equal to 98%, more preferably higher than or equal to99%, and again more preferably higher than or equal to 99.5%, again morepreferably higher than or equal to 99.8%, e.g. 99.9% for use as amedicament.

In a further aspect, the present invention provides for(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate for use as a medicament, wherein preferably saiddihydrogen phosphate has an ee of the (R) form higher than or equal to97%, preferably higher than or equal to 98%, more preferably higher thanor equal to 99%, and again more preferably higher than or equal to99.5%, again more preferably higher than or equal to 99.8%, e.g. 99.9%.

The present invention further provides for(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine aswell as the phosphate salt thereof, preferably the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, typically and preferably having an ee of the (R)form higher than or equal to 97%, preferably higher than or equal to98%, more preferably higher than or equal to 99%, and again morepreferably higher than or equal to 99.5%, again more preferably higherthan or equal to 99.8%, e.g. 99.9% for use in a method of the treatmentof a disease or disorder in humans including women of child bearingpotential and pediatric patients, in which aldosterone over-exposurecontributes to the deleterious effects of said disease or disorder,typically and preferably, wherein said disease or disorder is selectedfrom primary and secondary hyperaldosteronism, heart failure, chronicrenal failure, hypertension, restenosis, obesity, nephropathy,post-myocardial infarction, renal fibrosis, and coronary heart disease.

Further, the present invention provides for(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine aswell as the phosphate salt thereof, preferably the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, typically and preferably having an ee of the (R)form higher than or equal to 97%, preferably higher than or equal to98%, more preferably higher than or equal to 99%, and again morepreferably higher than or equal to 99.5%, again more preferably higherthan or equal to 99.8%, e.g. 99.9% for use in a method of the treatmentof a disease or disorder, wherein said disease or disorder is selectedfrom primary and secondary hyperaldosteronism, heart failure, chronicrenal failure, hypertension, restenosis, obesity, nephropathy,post-myocardial infarction, renal fibrosis, and coronary heart disease.Further preferably, said method is in particular suited for use inhumans including preferably for women of child bearing potential andpediatric patients.

In a further very preferred embodiment and aspect, the present inventionprovides for provides crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, preferably anhydrous crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, having an ee of the (R) form higher than or equalto 97%, preferably higher than or equal to 98%, more preferably higherthan or equal to 99%, and again more preferably higher than or equal to99.5%, again more preferably higher than or equal to 99.8%, e.g. 99.9%,for use in a method of treating a disease or disorder in a human,wherein said disease or disorder is selected from primary and secondaryhyperaldosteronism, heart failure, chronic renal failure, hypertension,restenosis, obesity, nephropathy, post-myocardial infarction, renalfibrosis, and coronary heart disease, wherein preferably said human is awoman of child bearing potential or a pediatric patient.

In a further very preferred embodiment and aspect, the present inventionprovides for provides crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, preferably anhydrous crystalline(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, having an ee of the (R) form higher than or equalto 97%, preferably higher than or equal to 98%, more preferably higherthan or equal to 99%, and again more preferably higher than or equal to99.5%, again more preferably higher than or equal to 99.8%, e.g. 99.9%,for use in a method of treating a disease or disorder in a human,wherein said disease or disorder is selected from primary and secondaryhyperaldosteronism, heart failure, chronic renal failure, hypertension,restenosis, obesity, nephropathy, post-myocardial infarction, renalfibrosis, and coronary heart disease, wherein preferably said human is awoman of child bearing potential or a pediatric patient, and whereinsaid(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate inhibits aromatase activity in the cell-free humanrecombinant aromatase enzyme assay described in Example 8 with an IC₅₀of 700 nM or more, preferably 750 nM or more, more preferably 800 nM ormore, more preferably 850 nM or more, more preferably 900 nM or more,more preferably 950 nM or more, more preferably 1000 nM or more, morepreferably 1050 nM or more, more preferably 1100 nM or more, morepreferably 1150 nM or more, more preferably 1200 nM or more, morepreferably 1250 nM or more, more preferably 1300 nM or more, morepreferably 1350 nM or more, more preferably 1400 nM or more, morepreferably 1450 nM or more, more preferably 1500 nM or more, morepreferably 1550 nM or more, most preferably at least 1600 nM, e.g. 1610nM or 1620 nM or 1630 nM or 1640 nM or at least 1650 nM.

In a further aspect, the present invention provides for a process forpreparing a compound selected from(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine and apharmaceutically acceptable salt thereof, and wherein very preferablysaid pharmaceutically acceptable salt is the phosphate salt thereof, andfurther preferably the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate. The inventive processes comprise the steps of: (i)reacting racemic5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine with a(−)-O,O′-acylated L-tartaric acid, in particular(−)-O,O′-dibenzoyl-L-tartaric acid to form the diastereomeric(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridinedibenzoyl-L-tartrate salt; and (ii) recrystallizing at least once thetartrate salt obtained in step i; and (iii) liberating the free base(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine byadding a base to a solution of said tartrate salt obtained in step ii;and optionally (iv) forming a pharmaceutically acceptable salt byreacting said free base with an acid, preferably with phosphoric acid(H₃PO₄). In one embodiment, said (i) reacting racemic5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine with a(−)-O,O′-acylated L-tartaric acid, in particular(−)-O,O′-dibenzoyl-L-tartaric acid to form the diastereomeric(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridinedibenzoyl-L-tartrate salt is effected in an alcoholic solution,preferably in a solution of ethanol, at a temperature of below about 50°C., preferably of below about 45° C., and further preferably of belowabout 40° C. In one embodiment, said (ii) recrystallizing at least oncethe tartrate salt obtained in step (i) is effected in anaqueous-alcoholic solution, preferably in an aqueous ethanolic solution,wherein preferably the ratio of water:ethanol is of about 2.4: about 10.

In one embodiment, the process for preparing a compound selected from(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine and apharmaceutically acceptable salt thereof of the invention does notcomprise a step of chiral resolution of5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine (fadrozole)by means of chiral preparative HPLC, wherein preferably said process forpreparing a compound selected from(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine and apharmaceutically acceptable salt thereof of the invention does notcomprise a step of chiral resolution of5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine (fadrozole)by means of chiral HPLC. Such step of chiral resolution by means ofchiral HPLC can typically comprise (i) repetitive chiral HPLCs on lowcapacity columns or (ii) preparative HPLC on high capacity column.

In a preferred embodiment, the process of the invention yields(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine andits pharmaceutically acceptable salts thereof, in particular thephosphate salt thereof, further preferably the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, with an ee of the (R) form higher than or equal to97%, preferably higher than or equal to 98%, more preferably higher thanor equal to 99%, and again more preferably higher than or equal to99.5%, again more preferably higher than or equal to 99.8%, e.g. 99.9%.

In a further preferred embodiment, the process of the invention yields(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine andits pharmaceutically acceptable salts thereof, in particular thephosphate salt thereof, further preferably(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, wherein said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine andits pharmaceutically acceptable salts thereof inhibit aromatase activityin the cell-free human recombinant aromatase enzyme assay described inExample 8 with an IC₅₀ of of 700 nM or more, preferably 750 nM or more,more preferably 800 nM or more, more preferably 850 nM or more, morepreferably 900 nM or more, more preferably 950 nM or more, morepreferably 1000 nM or more, more preferably 1050 nM or more, morepreferably 1100 nM or more, more preferably 1150 nM or more, morepreferably 1200 nM or more, more preferably 1250 nM or more, morepreferably 1300 nM or more, more preferably 1350 nM or more, morepreferably 1400 nM or more, more preferably 1450 nM or more, morepreferably 1500 nM or more, more preferably 1550 nM or more, mostpreferably at least 1600 nM, e.g. 1610 nM or 1620 nM or 1630 nM or 1640nM or 1650 nM or more.

The inventive processes, thus, utilize crystallization to obtain(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine andits pharmaceutically acceptable salts thereof, and very preferably itsphosphate salt thereof, and again further the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, in exceptional high chiral purity for commercialpharmaceutical use. On a commercial scale, crystallization is much moreadvantageous being more economical than chromatographic resolution byallowing for larger batch preparation, less expensive equipment andfacilities, and not requiring specialized expertise.

In one aspect, there is provided a pharmaceutical composition comprising(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine or apharmaceutically acceptable salt thereof, in particular a phosphatesalt, more preferably the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, as described herein in admixture with at least onepharmaceutically acceptable excipient.

In one embodiment, said pharmaceutical composition is provided in theform of tablets, pills, dispersible granules, cachets, capsules,powders, lozenges, suppositories or retention enemas.

EXAMPLES Equipment, Materials and Methods Specific Optical Rotation[α]_(D)

The Specific Optical Rotation [α]_(D) measurements were performed insolution using the sodium D-line at 589.3 nm of a standard Perkin ElmerPolarimeter 343. For the measurement 1 gram of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine-dihydrogen-phosphatewas dissolved in 100 ml of the respective solvent and this solution wastransferred in an optical cuvette of 1 decimeter length. The measurementwas done at a temperature of 20° C. or 25° C., respectively. TheSpecific Optical Rotation [α]_(D) is calculated by the formula100×α/(1×c) where: α=observed rotation in degrees; 1=cell path length indecimeters; c=concentration in grams per 100 ml.

Elemental Analysis

Elemental analysis was performed on standard equipment (e.g. vario ELcube elemental analyzer) and the values for carbon, hydrogen andnitrogen were determined.

Chiral HPLC

The chiral HPLC was performed on an Agilent 1100 series LC22 instrumentwith the following column specifications and conditions:

Column: Chiralpack AD-H, granulometry: 5 μm, 250×4.6 mm; no.ADH0CE-TF087Mobile phase: Ethanol+0.1% diethylamine (DEA)Detector wavelength: 230 nmOven temperature: 25° C.Flow rate: 0.5 mL/minInjection volume: 5 μLSample preparation: 0.5 mg/mL in Ethanol+0.1% DEA

XRPD

The X-ray powder diffraction studies were performed using a Bruker AXSD2 PHASER in Bragg-Brentano configuration. Using a Cu anode at 30 kV, 10mA; sample stage standard rotating; monochromatisation by a Kβ-filter(0.5% Ni). Slits: fixed divergence slits 1.0 mm (=0.61°), primary axialSoller slit 2.5°, secondary axial Soller slit 2.5°. Detector: Lineardetector LYNXEYE with receiving slit 5° detector opening. The standardsample holder (0.1 mm cavity in (510) silicon wafer) had a minimalcontribution to the background signal. Measurement conditions: scanrange 5 to 45° 2theta, sample rotation 5 rpm, 0.5s/step, 0.010°/step,3.0 mm detector slit; and all measuring conditions were logged in theinstrument control file. As system suitability, corundum sampleA26-826-S (NIST standard) was measured daily.

The software used for data collection was Diffrac.Commander v2.0.26.Data analysis was done using Diffrac.Eva v1.4. No background correctionor smoothing was applied to the patterns.

Single Crystal X-Ray Analysis

Single crystals of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridine-dihydrogen-phosphatewere grown using a n-propanol/water mixture as solvent. A suitablesingle crystal was taken out of the mother liquor, immediately coatedwith high viscosity oil, cut to size and mounted on a Mitagen Microloopand shock frozen to 150 K. The measurement was performed on a Bruker D8Quest instrument with MoKα radiation, using φ-scans and ω-scans. Themolecular structure was subsequently solved by direct method (SHELXTsoftware). All non-hydrogen atoms were refined with anisotropictemperature factors. On the completed model, Bijovet analysis wasperformed to determine the absolute configuration.

TGA/DSC

The thermogravimetric analysis and differential scanning calorimetry(TGA/DSC) studies were performed using a Mettler Toledo TGA/DSC1 STAReSystem with a 34-position auto sampler. The samples were made using AIcrucibles (40 μL; pierced). Typically 5-10 mg of sample was loaded intoa pre-weighed Al crucible and was kept at 30° C. for 5 minutes, afterwhich it was heated at 10° C./min from 30° C. to 350° C. A nitrogenpurge of 40 ml/min was maintained over the sample. The software used fordata collection and evaluation was STARe Software v12.10 build 5937. Nocorrections were applied to the thermogram.

DSC

The DSC studies were performed using a Mettler Toledo DSC STARe System.The samples were made using Al crucibles (40 μL; pierced). Typically 1-8mg of sample was loaded onto a pre-weighed Al crucible and was kept at30° C. for 5 minutes, after which it was heated at 10° C./min from 30°C. to 350° C. and kept at 350° C. for 1 minute. A nitrogen purge of 40ml/min was maintained over the sample. As system suitability checkIndium and Zinc were used as references. The software used for datacollection and evaluation was STARe Software v12.10 build 5937. Nocorrections were applied to the thermogram.

DVS

The Dynamic Vapour Sorption (DVS) studies were performed using a SurfaceMeasurement Systems Ltd. DVS-1 No Video. The sample was loaded into abalance pan, typically 20-30 mg, and equilibrated at 0% RH. After thematerial was dried, the RH was increased with 10% per step for 1 hourper increment, ending at 95% RH. After completion of the sorption cycle,the sample was dried using the same method. The software used for datacollection was DVSWin v3.01 No Video. Data analysis was performed usingDVS Standard Analysis Suite v6.3.0 (Standard).

Solubility

The solubility was determined using the shake-flask method; thesolubility was visually determined at 20° C. The listed solvents wereadded stepwise to 10 mg of compound, with 15 minutes in betweenadditions, until complete dissolution was obtained or a solubility ofless than 0.05 mg/ml was reached.

High Throughput Experimentation

High throughput experimentation was performed in well-plate format usinga Freeslate Core Module 2 in crystallization configuration equipped witha Julabo FPSO for temperature control of the cooling crystallizationexperiments.

Solid Dispense System

Solids were dispensed using a Freeslate Core Module Protégé SolidDispense System in classic and SV-hopper configuration with a Sartoriusbalance. Hoppers that were used were 25 ml classic hoppers with 8 mmvalve size and 4 to 3 mm funnel size, 10 ml classic hoppers with 8 mmvalve size and 4 to 3 mm funnel size and SV hoppers with standard 4 mlglass vials.

Racemic 5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine

The title compound (fadrozole) may be prepared e.g., according to theprocedure described by L. J. Browne et al. (J. Med. Chem. 1991, 34,725.) or obtained by commercial suppliers such as Sigma-Aldrich.

Example 1 Diastermomeic Salt Screening with racemic5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine

100 mg (1.0 eq) of the title compound were dissolved in isopropanol,followed by addition of a solution of chiral acid (0.5 eq) inisopropanol (0.5 mL). The result of the screening is summarized in Table2.

TABLE 2 Summary of enantioselective salt crystallization experimentsFormula Chiral acid MW Condition Result L-(+)-Tartaric acid C₄H₆O₆ 10 VNo crystallization CAS: 87-69-4 150.09 5 V Formation of 0.5 eq a gum(−)-O,O′-Dibenzoyl-L- C₁₈H₁₄O₈•H₂O 10 V Crystallization tartaric acidmonohydrate 376.34 0.5 eq ee: 55% CAS: 62708-56-9 L-(−)-Malic acidC₄H₆O₅ 10 V No crystallization CAS: 97-67-6 134.09 5 V 0.5 eqL-(+)-Mandelic acid C8H8O3 10 V No crystallization CAS: 17199-29-0152.15 5 V 0.5 eq (1S-(+)-10- C₁₀H₁₆O₄S 10 V No crystallizationCamphorsulfonic acid 223.30 5 V CAS: 3144-16-9 0.5 eq

Example 2 Salt Screening with(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridineGeneral Procedure:

The title compound (free base) was dissolved in ethanol (at 100 g/L) at35° C., followed by addition of the acid at the same temperature. Theresulting mixture was cooled to 10° C. at a cooling rate of −20° C./hand the precipitate (if any) was filtered off, washed with ethanol anddried under reduced pressure (at 50° C.).

The result of the salt screening is summarized in Tables 3 to 5.

TABLE 3 Summary of salt screening experiments with ethanol as solventSalt forming acid Stoichiometry (eq) Result fumaric acid 1:1 oiltartaric acid 1:1 solid sulfuric acid 1:1 oil phosphoric acid* 1:1 solidadipic acid 1:1 oil glucuronic acid* 1:1 no salt isolated glutaric acid1:1 oil malic acid 1:1 oil malonic acid 1:1 oil fumaric acid 1:2 solidtartaric acid 1:2 solid adipic acid 1:2 oil glutaric acid 1:2 oil malicacid 1:2 oil malonic acid 1:2 oil *slurry

TABLE 4 Summary of salt screening experiments with methanol as solventCounter ion Stoichiometry (eq) Result fumaric acid 1:1 solid tartaricacid 1:1 oil sulfuric acid 1:1 oil phosphoric acid* 1:1 solid adipicacid 1:1 oil glucuronic acid* 1:1 oil glutaric acid 1:1 oil malic acid1:1 oil malonic acid 1:1 oil fumaric acid 1:2 solid tartaric acid 1:2oil adipic acid 1:2 counter ion salt glutaric acid 1:2 oil malic acid1:2 oil malonic acid 1:2 oil *slurry

With the phosphate salt, the tartrate salt and the fumarate salt thatwere obtained as solids, a solid state characterization according toTable 5 was performed.

TABLE 5 Solid state characterization Criterion Phosphate salt Tartratesalt Fumarate salt Crystallinity good good good Water solubility goodgood good Polymorph tendency Not Not 2 polymorphs (XRPD) observedobserved observed Hygroscopicity (DVS) low high medium Solid phasetransition Not Not 2 polymorphs (XRPD) observed observed observedSolvation anhydrous anhydrous anhydrous Melting point 189° C. 150° C.120° C. (DSC/TGA)

Example 3 Preparation of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate (Crystalline Form I) Step 1: Preparation of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedibenzoyl-L-tartrate

In a 10 L reactor were loaded at 20° C. racemic5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine (328 g, =1.0eq) and ethanol (2.3 L). The mixture was heated to 40° C. then asolution of (−)-O,O-dibenzoyl-L-tataric acid (276.4 g, 0.5 eq) inethanol (1 L) was added. The mixture was maintained at 40° C. for 1h,then cooled to 20° C. over a period of 2h, maintained for 1h at thistemperature, then cooled to 10° C. over a period of 0.5 hand finallymaintained at 10° C. overnight. The precipitate was subsequentlyfiltered off and the filter cake was washed with cold (0° C.) ethanol (1L) to afford the title compound as a white humid powder (485 g, =413.7 gestimated dry, by loss on drying, 48.4%, ee=87%).

Step 2: Recrystallization of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedibenzoyl-L-tartrate

In a 10 L reactor were loaded at 20° C.(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedibenzoyl-L-tartrate (485 g, ee=87%, =413.7 g estimated dry, by loss ondrying, =1.0 eq) obtained from step 1, ethanol (10 L, 24 V) and water(2.4 L, 6V). The resulting mixture was heated to reflux, whereupon asolution was formed. The solution was then cooled to 50° C. andmaintained at this temperature for 1 h. Subsequently, the mixture wasallowed to cool to 10° C. over a period of 2 h and then maintained atthis temperature overnight. The precipitate was filtered off and thefilter cake was washed with cold (0° C.) ethanol (1.2 L). The productwas dried under reduced pressure at 40° C. to afford the title compoundas a white powder (294.8 g, 71%, single enantiomer). EnantiomericExcess: >99.9% as determined by HPLC

Step 3: Preparation of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine (FreeBase)

In a 2 L reactor were loaded(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedibenzoyl-L-tartrate (177 g, single enantiomer) obtained from step 2 anddichloromethane (1.77 L, 10 V). T en, a solution of Na₂CO₃ (71 g, 2.2eq) in water (875 mL) was added. After 0.25 h stirring at roomtemperature, the mixture was decanted. The liquid phases thus obtainedwere limpid and the aqueous phase had a pH of 8-9. The organic phase waswashed with water (2×875 mL) and then concentrated under vacuum. Theresidue was dissolved in ethanol and again concentrated under vacuum toafford the title compound (70 g, quant.) as an oil which solidified uponstanding.

Step 4:(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate

In a 1 L reactor were loaded(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine (94g, 1.0 eq) and ethanol (564 mL) and the mixture was heated to 35° C. Thesolution was filtered and the reactor was rinsed with ethanol (94 mL). Asolution of H₃PO₄ (97 g, 85% wt/wt in H₂O) in ethanol (235 mL) was addedat the same temperature, rinsing with ethanol (47 mL). After stirringfor 1 h at 35° C., the mixture was cooled to 10° C. (at a rate of −20°C./h) and kept at this temperature for 10 h. The resulting solid wasfiltered off and the filter cake was washed with cold (10° C.) ethanol(3×94 mL). After drying at 50° C. under reduced pressure, the titlecompound was obtained as a white, crystalline, free flowing powder (100g, 74%).

XRPD: see FIG. 1 and Table 1

Melting Point: 189° C. as determined by TGA/DSC (FIG. 2).Enantiomeric Excess: >99.9% (FIG. 3). The chiral HPLC for thedetermination of the enantiomeric excess of the preparation featured aretention time (tr) of 14.459 min for the R-(+)-enantiomer and 9.814 Minfor the S-(−)-enantiomer.Absolute configuration: R-(+)-on carbon 5 as determined by singlecrystal X-ray.Specific optical rotation (CH₃CN:H₂O 1:1 (v/v)): [α]_(D) ²⁰=+98.1Hygroscopicity: 1.0% at ≥90% relative humidity (RH) as determined byDVS. Water uptake is reversible and crystalline form does not changeupon DVS treatment (FIGS. 4 to 6). Mass loss upon heating up until 225°C. is 1.4% as determined by TGA/DSC (FIG. 2). The crystals of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate were further characterized by their elementalanalysis, which is in accordance with the values calculated from themolecular formula C₁₄H₁₆N₃O₄P (MW:321.27): C 52.4%; H 5.1%; N 13.03%.

Example 4 Preparation of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridine-chloridefrom(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydro-imidazolium[1,5-a]pyridinedihydrogen phosphate Via the Free Base

(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydro-imidazolium[1,5-a]pyridinedihydrogen phosphate (1000 mg, 3.11 mmol,) as prepared in Example 3 wassuspended in Et₂O (30 ml) and extracted with saturated aqueous NaHCO₃solution (30 ml). The aqueous layer was extracted with diethyl-ether(2×20 ml) and the combined organic layers were washed with brine (10 ml)and distilled water (10 ml), dried over Na₂SO₄, filtered and evaporatedto obtain the free base(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine as awhite solid which was dried in vacuum over night at 50° C. (530 mg).

Melting point: 101-102° C.; Specific optical rotation (ethanol): [α]_(D)²=+127.3;

The so obtained(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine (100mg, 0.447 mmol, 1 eq) was dissolved in methylene chloride (2.2 ml) andHCl (2 M in diethylether, 0.34 ml, 0.76 mmol, 1.5 eq) was added and themixture was stirred for 30 minutes at RT, then evaporated and driedunder vacuum at 80° C.(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydro-imidazolium[1,5-a]pyridinechloride was isolated as a crystalline solid.

Melting point: 240-243° C.; Specific optical rotation (ethanol): [α]_(D)²⁰=+104.8; Specific optical rotation (CH₃CN:H₂O 1:1 (v/v)): [α]_(D)²=+124.4.

Example 5 Hygroscopicity of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydro-imidazolium[1,5-a]pyridine-dihydrogenphosphate Compared to(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydro-imidazolium[1,5-a]pyridine-chloride

100 mg samples of the two crystalline salts were stored in open flasksfor 24 hours side by side at room temperature in unconditioned ambientair and weight measurements occurred at time 0 and after 24 hours (Table6).(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydro-imidazolium[1,5-a]pyridinedihydrogen phosphate shows a weight increase of 0.57% and is consideredto be non-hygroscopic as compared to the significant hygroscopicity ofthe corresponding(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinechloride evidenced by the 13.1% weight increase.

TABLE 6 Comparison of hygroscopic properties Phosphate Salt ChlorideSalt Absolute Weight Absolute Weight Time weight increase weightincrease  0 hours 103.3 mg — 100.1 mg — 24 hours 103.9 mg 0.57% 113.2 mg13.1%

Example 6 Shake-Flask Solubility Study of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate

A shake-flask solubility study was performed on the material accordingto U.S. Pharmacopoeia (USP) specifications. A set of pharmaceuticallyaccepted process solvents with different functional groups has been usedto determine the shake-flask solubility. The solvents were allowed toevaporate at 0-100 mbar at room temperature overnight. All solids havethen been subsequently analysed using XRPD. The results of this studycan be found in Table 7 below.

TABLE 7 Shake-flask solubility results of the different batches Samplecode Solvent Solubility (mg/ml) USP classification DF1181-5-S1 Methanol112-1120 Freely soluble DF1181-5-S2 Dichloromethane <0.10 Practicallyinsoluble DF1181-5-S3 Methyl tert-butyl ether <0.11 Practicallyinsoluble DF1181-5-S4 Acetone <0.09 Practically insoluble DF1181-5-S5Ethyl acetate <0.09 Practically insoluble DF1181-5-S6 Ethanol 0.1-1.0 Very slightly soluble DF1181-5-S7 Acetonitrile <0.11 Practicallyinsoluble DF1181-5-S8 n-Heptane <0.11 Practically insoluble DF1181-5-S9Water >1000 Freely soluble DF1181-5-S10 Toluene <0.10 Practicallyinsoluble DF1181-5-S11 Acetic acid 118-1180 Freely soluble

The material is very soluble in water, freely soluble in methanol andacetic acid, very slightly soluble in ethanol and practically insolublein the other tested solvents. In Table 8 the XRPD results of theperformed measurements on either the solids of the slurry or the solidsof the solution after evaporation are given.

TABLE 8 XRPD results after solubility determination Sample code XRPDDF1181-5-S1 Form I - Conform starting material DF1181-5-S2 Form I -Conform starting material DF1181-5-S3 Form I - Conform starting materialDF1181-5-S4 Form I - Conform starting material DF1181-5-S5 Form I -Conform starting material DF1181-5-S6 Form I - Conform starting materialDF1181-5-S7 Form I - Conform starting material DF1181-5-S8 Form I -Conform starting material DF1181-5-S9 Form I - Conform starting materialDF1181-5-S10 Form I - Conform starting material DF1181-5-S11 Amorphous

No new polymorphic form was obtained after evaporation of the solvents,except for acetic acid (amorphous), confirming the exceptional stabilityof crystalline form I.

Example 7 Polymorph Study on(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate

Solvents and co-solvents were added in different ratios. The differentratios were 100% solvent and 0% co-solvent, 80% solvent and 20%co-solvent, 60% solvent and 40% co-solvent, 40% solvent and 60%co-solvent, 20% solvent and 80% co-solvent and 5% solvent and 95%co-solvent, subsequently. Table 9 shows the layout of the studyconditions and the respective XRPD conclusions on polymorphic forms.

TABLE 9 Layout of the 96-well polymorph study master plate Well positionSolvent Co-solvent XRPD 1-6 Formic acid Water Form I  7-12 2-Butanonen-Heptane Form I 13-18 Acetic acid Water Form I 19-24 Cyclohexanonen-Heptane Form I 25-30 Methanol Water Form I 31-36 Ethylacetaten-Heptane Form I 37-42 Ethanol Water Form I 43-48 Isopropyl acetaten-Heptane Form I 49-54 2-Propanol Water Form I 55-60 Cyclopentyl methylether n-Heptane Form I 61-66 Acetone Water Form I 67-72 Toluenen-Heptane Form I 73-78 Acetonitrile Water Form I 79-84 Cyclohexanen-Heptane Form I 85-90 Tetrahydrofuran Water Form I 91-96 Chlorobenzenen-Heptane Form I

The starting material was dispensed (30 mg) in a 96-well plate (“masterplate”) using a Freeslate CM Protégé solid dispense system. After soliddispense the well plate was transferred to the Freeslate Core Module 2for liquid dispenses (solvent+co-solvent total=800 μL). The master platewas allowed to stir for 2 h at 50° C. An aliquot of the samples in themaster plate was transferred to a cooling crystallization plate via ahot filtration plate. The samples in the cooling plate were then allowedto cool from 50° C. to 10° C. over a period of 5 hours using a cubiccooling rate. None of the wells contained solids, so to simulateevaporative crystallization the solvents were allowed to evaporate at0-100 mbar at RT. All of the formed solids were analysed using XRPD. Alldiffractograms were compared with the reference diffractogram asoutlined in FIG. 1 by overlaying the respective diffractograms (FIG. 6).In this study, only one polymorph of the title compound, form I, couldbe identified having the described very beneficial and surprisingproperties. This finding seems to confirm that crystallization is notonly a function of salt selection but also of crystallization processconditions leading to the inventive form I of the(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate (P. Heinrich Stahl (Editor), Camille G. Wermuth(Editor); Handbook of Pharmaceutical Salts: Properties, Selection, andUse, 2nd Revised Edition, March 2011, Wiley-VCH, ISBN:978-3-90639-051-2).

Example 8 Assessment of Aromatase and Aldosterone Synthase Inhibition by(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate Human NCI-H295R Cell Assay for Aldosterone Synthase(CYP11B2) and Aromatase (CYP19) Activities

NCI-H295R cells, a continuous cell line derived from an invasive primaryadrenocortical carcinoma were obtained from CLS cell line services GmbH(catalog No. 300483). Because NCI-H295R cells produce both aldosteroneand estradiol, they enable measuring aldosterone synthase activity andaromatase activity under identical conditions. Prior to being used forthe assays the cells were maintained in DMEM/Ham's medium with 15 mMHEPES and 1.2 g NaHCO₃ supplemented with 5% steroid-free serumreplacement, Panexin BMM (PAN Biotech, Aldenbach, Germany; cat. no.P04-9515A2), 1% Penicillin/Streptomycin, 1.25% L-Glutamine, and 6.25μg/ml insulin, 6.25 ng/ml selenium, 5.35 μg/ml linoleic acid and 1.25mg/ml bovine serum albumin. The cells were maintained at 37° C. under anatmosphere of 95% air/5% CO₂. For the assays the cells were sub-culturedat a density of 5×10⁵ cells per well in 24-well plates and grown until50-60% confluency (48 h). The growth medium then was replaced with 500μl serum-free DMEM:Ham's F12 containing the test compound dissolved inethanol/water 1:1 (v/v) so that the final concentration in the assayconsisted of 0.5% ethanol. Six concentrations were evaluated, andcontrol samples with no compound were supplemented with 0.5% ethanol.The cells with compound were incubated at 37° C. under 95% air/5% CO₂for 6h. After which the supernatant was removed and stored at −20° C.until analysis. After the supernatant was removed the cells wereevaluated to assure viability by optical evaluation utilizing phasecontrast microscopy examination for morphological changes and by theresazurin method which measures the conversion of resazurin into afluorescent end product resorufin. Non-viable cells lack the metaboliccapacity to make the conversion. The conversion was quantified bymeasuring the fluorescence at 544 nm/590 nm (extinction/emission)respectively using a Wallac 1420 Multiple Counter VictorFluorometer/Luminator (Perkin Elmer, Wlatham, Mass.).

Quantification of aldosterone concentration as a measure of aldosteronesynthase activity was accomplished by LC-MS as follows. Prior toanalysis acetonitrile was used to precipitate the sample protein andfollowing centrifugation the particle free supernatant was subject toLC-MS. The HPLC system consisted of an Accela U-HPLC pump and AccelaOpen auto sampler (Thermo Fisher Scientific, Waltham, Mass.). Massspectrometry was performed using a Q-Exactive MS (Orbitrap) equippedwith a heated electrospray (H-ESI) interface connected to a PC runningthe standard Xcalibur software 2.2 (Thermo Fisher Scientific, Waltham,Mass.). The LC was performed in the gradient mode using acetonitrilewith 0.1% formic acid (solvent A) and aqueous 0.1% formic acid solventB. The pump flow rate was set to 600 μl/min, and separation wasperformed on a Kinetex Phenyl-Hexyl 2.6 μm, 50×2.1 mm analytical column(Phenomenex, Germany) with a C6-Phenyl, 4×2.0 mm ID pre-column forquantification. As MS tune file a generic tune file was used and as alock mass for internal calibration the [M+H]⁺ ion of the disooctylphthalate (m/z 391.28492) present in the solvent system was used. FullMS-SIM analysis (m/z: 250-400) was applied with the mass resolution ofthe Orbitrap™ set to 35,000. The sample injection volume was 20 μl forall samples. The results were displayed as ng/ml and inhibition ofaldosterone production was expressed as percent inhibition relative tountreated controls i.e., in absence of any inhibitor (Table 10). IC₅₀values were calculated using linear interpolation using theconcentrations of test compound and the corresponding percentageinhibition that are immediately above and below 50% as illustratedbelow:

IC₅₀=(50%−Low_(inh)%)/(High_(inh)%−Low_(inh)%)×(High_(conc)−Low_(conc))+Low_(conc)

where “inh” is inhibition and “conc” is concentration.

TABLE 10 Inhibition of aldosterone production by (R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5- a]pyridinedihydrogen phosphate in NCI-H295R cells. Mean Inhibition (%)Concentration (nM) (3 determinations) Standard Deviation 10'000 100.00.0  1'000 100.0 0.0   100 100.0 0.0     10^(a) 60.8^(c) 4.0     1^(b)8.7^(d) 13.0    0.1 −19.6 9.9 ^(a)High_(conc) = the lowest concentrationof the test item that inhibits by at least 50% (10 nM) ^(b)Low_(conc) =the highest concentration of the test item that inhibits less than 50%(1 nM) ^(c)High_(inh) = percent inhibition achieved at the High_(conc)of the test item (60.8%) ^(d)Low_(inh) = percent inhibition achieved atthe Low_(conc) of the test item (8.7%) IC₅₀ = (50% − 8.7%)/(60.8% −8.7%) × (10 nm − 1 nM) + 1 nM = 8.1 nM IC₅₀ = 8.1 nM for inhibition ofaldosterone production (aldosterone synthase activity)

Aromatase activity was measured by quantification of the estradiolconcentration in the supernatant from incubation of NCI-H295R cells asdescribed above for determination of aldosterone synthase activityexcept that much higher concentrations of the inhibitor, as indicatedbelow were used to obtain an IC50. Quantification of estradiolconcentration was accomplished using a 17-beta-estradiol ELISA kit fromIBL-Hamburg (Hamburg, Germany) according to the manufacturer'sinstructions. A standard curve was generated by plotting the absorbanceof each reference standard (y-axis) against the corresponding logconcentration (x-axis). The absorbance of each sample was used todetermine the corresponding values by interpolation from the standardcurve using GraphPad Prism 5.04 software (GraphPad Software Inc., SanDiego, Calif.). An IC₅₀ was calculated using the formula described abovefor the aldosterone synthase data disclosed in Table 11.

TABLE 11 Inhibition of estradiol production by (R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5- a]pyridinedihydrogen phosphate in NCI-H295R cells. Mean Inhibition (%)Concentration (μM) (3 determinations) Standard Deviation 1000 80.4 1.6 100 82.8 0.8   10^(a) 68.6^(c) 5.3    1^(b) 29.1^(d) 8.4    0.1 12.55.3     0.01 −1.5 14.8 ^(a)High_(conc) = the lowest concentration of thetest item that inhibits by at least 50% (10 μM) ^(b)Low_(conc) = thehighest concentration of the test item that inhibits less than 50% (1μM) ^(c)High_(inh) = percent inhibition achieved by the High_(conc) ofthe test item (68.6%) ^(d)Low_(inh) = percent inhibition achieved by theLow_(conc) of the test item (29.1%) IC₅₀ = (50% − 29.1%)/(68.6% − 29.1%)× (10 μM − 1 μM) + 1 μM = 5.76 μM or 5760 nM IC₅₀ = 5760 nM forinhibition of estradiol production (aromatase activity)

Cell-Free Human Recombinant Aromatase Assay

Aromatase (CYP19) activity was measured using a human CYP19 assay kit(Corning®, Corning, N.Y.; Product #456260) according to themanufacturer's instructions. The assay system utilized a recombinanthuman enzyme, a fluorometric substrate MFC(7-methyl-4-trifluoro-methyl-Coumarin), and an NADPH regenerating systemconsisting of glucose-6-phosphate dehydrogenase, NADP⁺, andglucose-6-phospahate. For determining the concentrations of the testcompounds which inhibited the enzyme activity by 50% (IC₅₀) eight testconcentrations were tested. The test compounds were dissolved inethanol/water 1:1 (v/v) so that the final ethanol concentration in theassay was 1%. The test compounds at various concentrations along withthe NADPH regenerating system were added to 96-well plates. After a 10min pre-incubation the reaction was started by the addition ofpre-warmed enzyme substrate mix and allowed to continue for anadditional 30 min at 37° C. The reaction was then stopped by theaddition of a solution of 80% acetonitrile and 20% 0.5M Tris base (stopsolution). To control for background fluorescence, blank wells(containing no test samples) were also assayed but these wells had thestop solution added prior to the addition of the enzyme substratemixture. The fluorescent product formed,7-hydroxy-4-triflouro-methyl-Coumarine (HFC) was detected using a Wallac1420 Multiple Counter Victor Fluorometer/Luminator (Perkin Elmer,Wlatham, Mass.). The wave lengths for excitation and emission were 405and 535 nm, respectively. The data was compiled with standard softwareWallac 1420 Manager 3.0. In addition to subtraction of the blank wellsamples as indicated above, each test substance was pre-tested forauto-fluorescence. For this purpose the NADPH generating system(cofactor mix) and the enzyme/substrate-mix were replaced by acomparable mixture of control protein, assay buffer, and test compoundsolvent. These control samples were then pre-incubated and assayed andas described above. Three independent determinations of the IC₅₀ weremade from line of best fit plots of % inhibition versus inhibitorconcentration (Table 12).

TABLE 12 Inhibition of human recombinant aromatase activity by(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5- a]pyridinedihydrogen phosphate. Trial Half-maximal inhibitory (8 concentrations ofconcentration inhibitor per trial) IC₅₀ (nM) 1 1694 2 1557 3 1668 Mean1640 Standard deviation ±72.5

Example 9 Assessment of Stability Data for(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate

Long-term stability data relevant and important for regulatoryconsiderations have been measured. Hereto, various tests as indicated inbelow Tables 13 to 15 have been conducted at either 25° C. and 60% RH(Table 13), at 30° C. and 65% RH (Table 14), and at 40° C. and 75% RH(Table 15) each test at various time points (initial, after 1, 3 and 6months or even longer).

It has been shown that(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate is very stable over a long and extended period oftime, and that in particular long-term stability has been shown withrespect to purity, water content and thus hygroscopicity as well aschiral purity under the assessed stability conditions and time periods.Moreover, and importantly, no change of polymorphism was observed atneither assessed condition and time periods.

TABLE 13 Stability data at stability conditions 25° C./60% RH for(R)-(+)-5- (p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate. 1 3 6 9 12 Test Initial month months months monthsmonths Appearance White White White White White White powder powderpowder powder powder powder Assay by HPLC, 99.9 99.5 99.8 99.6 99.7100.3 anhydrous, solvent free Purity by HPLC 99.87 99.77 99.81 99.8299.84 99.81 Water content 0.3 0.2 0.2 0.2 0.2 0.3 ChiralPurity >99.5 >99.5 >99.5 >99.5 >99.5 >99.5 Polymorph by XRPD ConformConform Conform Conform Conform Conform to initial to initial to initialto initial to initial to initial

TABLE 14 Stability data at stability conditions 30° C./65% RH for(R)-(+)-5- (p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate. 1 3 6 9 12 Test Initial month months months monthsmonths Appearance White White White White White White powder powderpowder powder powder powder Assay by HPLC, 99.9 99.6 100.1 99.6 99.699.5 anhydrous, solvent free Purity by HPLC 99.87 99.76 99.81 99.8499.86 99.85 Water content 0.3 0.2 0.3 0.2 0.2 0.3 ChiralPurity >99.5 >99.5 >99.5 >99.5 >99.5 >99.5 Polymorph by XRPD ConformConform Conform Conform Conform Conform to initial to initial to initialto initial to initial to initial

TABLE 15 Stability data at stability conditions 40° C./75% RH for(R)-(+)-5- (p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate. Test Initial 1 month 3 months 6 months AppearanceWhite White White White powder powder powder powder Assay by HPLC, 99.999.7 100.2 99.2 anhydrous, solvent free Purity by HPLC 99.87 99.80 99.7999.88 Water content 0.3 0.3 0.5 0.3 ChiralPurity >99.5 >99.5 >99.5 >99.5 Polymorph by XRPD Conform to Conform toConform to Conform to initial initial initial initial

1. A compound selected from(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine and apharmaceutically acceptable salt thereof, wherein said compound has anenantiomeric excess of the (R) form higher than or equal to 97%.
 2. Thecompound of claim 1, wherein said compound inhibits aromatase activityin a cell-free human recombinant aromatase enzyme assay with an IC₅₀ of700 nM or more.
 3. The compound of claim 1, wherein said compoundinhibits aldosterone synthase in a NCI-H295R adrenal cell assay with anIC₅₀ of 100 nM or less.
 4. The compound of claim 1, wherein saidcompound has a selectivity for aldosterone synthase over aromatase of 50or more, wherein said selectivity is determined by a ratio of the IC₅₀values for inhibition of aromatase and aldosterone synthase; wherein theIC₅₀ values for inhibition of aldosterone synthase and aromatase areboth measured in the NCI-H295R adrenal cell assay.
 5. The compound ofclaim 1, wherein said compound is(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate.
 6. The compound of claim 1, wherein saidpharmaceutically acceptable salt is crystalline.
 7. The compound ofclaim 1, wherein said pharmaceutically acceptable salt is anhydrous. 8.The compound of claim 1, wherein said pharmaceutically acceptable saltis non-hygroscopic.
 9. The compound of claim 5, wherein said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate has a melting point of equal or between 184° C. to193° C. as determined by thermogravimetry analysis/differential scanningcalorimetry (TGA/DSC).
 10. The compound of claim 5, wherein said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate is a crystalline form I of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, wherein said crystalline form I has an X-raypowder diffraction pattern comprising 2θ values measured using CuKαradiation: 19.504; 21.919 and 24.159, wherein each peak may vary by±0.5.
 11. The compound of claim 1, wherein said compound is(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine. 12.(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate.
 13. A pharmaceutical composition comprising acompound according to claim 1 in admixture with at least onepharmaceutically acceptable excipient.
 14. A method of treating adisease or disorder in a human in need thereof including premenopausalfemale and pediatric patients, in which aldosterone over-exposurecontributes to deleterious effects of said disease or disordercomprising administering an effective amount of compound according toclaim 1 to said human.
 15. A process for preparing a compound selectedfrom (R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridineand a pharmaceutically acceptable salt thereof according to claim 1comprising the steps of: i. reacting racemic5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine with(−)-O,O′-dibenzoyl-L-tartaric acid to form the diastereomeric(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridinedibenzoyl-L-tartrate salt; and ii. recrystallizing at least once thetartrate salt obtained in step i; and iii. liberating the free base(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazo[1,5-a]pyridine byadding a base to a solution of the tartrate salt obtained in step ii;and optionally iv. forming a pharmaceutically acceptable salt byreacting said free base with an acid, wherein preferably said acid isphosphoric acid (H₃PO₄).
 16. The compound of claim 1, wherein saidcompound has a selectivity for aldosterone synthase over aromatase of100 or more, wherein said selectivity is determined by a ratio of theIC₅₀ values for inhibition of aromatase and aldosterone synthase andwherein the IC₅₀ values for inhibition of aldosterone synthase andaromatase are both measured in a NCI-H295R adrenal cell assay.
 17. Thecompound of claim 5, wherein said(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate is a crystalline form I of(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate, wherein said crystalline form I has an X-raypowder diffraction pattern comprising 2θ values measured using CuKαradiation: 19.504; 21.919 and 24.159, wherein each peak may vary by ±0.2degrees.
 18. A pharmaceutical composition comprising(R)-(+)-5-(p-cyanophenyl)-5,6,7,8-tetrahydroimidazolium[1,5-a]pyridinedihydrogen phosphate in admixture with at least one pharmaceuticallyacceptable excipient.
 19. The pharmaceutical composition according toclaim 18, wherein said pharmaceutical composition is in a tablet, pill,dispersible granule, cachet, capsule, powder, lozenge, suppository orretention enema form.
 20. The method according to claim 14, wherein saiddisease or disorder is selected from primary and secondaryhyperaldosteronism, heart failure, chronic renal failure, hypertension,restenosis, obesity, nephropathy, post-myocardial infarction, renalfibrosis, and coronary heart disease.